public class demo37 {
    //翻转二叉树  （递归）
  /*  class Solution {
        public TreeNode invertTree(TreeNode root) {
            if(root == null) return root;
            TreeNode left = invertTree(root.left);
            TreeNode right = invertTree(root.right);
            root.left = right;
            root.right = left;
            return root;
        }
    }*/
}
